Di-peptidyl peptidase IV (DPP-IV, EC3.4.14.5) is a serine protease which hydrolytically cleaves an N-terminal dipeptide from the N-terminus of an L-proline- or L-alanine-containing polypeptide. DPP-IV inhibitors exert their functions by enhancing the activity of incretins, and are non-insulin therapeutic drugs. DPP-IV inhibitors do not cause adverse effects such as body-weight gain and edema.
Patent application PCT/CN2015/078923 discloses a novel pyran derivative (2R,3S,5R,6S)-2-(2,5-difluorophenyl)-5-(2-(methylsulfonyl)-pyrrolo[3,4]pyrazol-5(2H,4H,6H)-yl)-6-(trifluoromethyl)tetrahydro-2H-pyran-3-amine as represented by structural formula (I) below, referred to as Compound A herein. This structure shows good inhibition on DPP-IV, and has a potential of preventing and/or treating type II diabetes.
